Seventy years ago this month – on 8 January 1940, to be precise – food rationing was introduced to Great Britain, and it wouldn't finally be shown the door for another 14 years. That means that anyone who was a toddler at the start of the Second World War would have been of school-leaving age when meat and bacon were finally taken "off the coupon" in the summer of 1954. Understandably, childhood obesity wasn't seen as a problem.

To mark the anniversary, TV chef Valentine Warner, of BBC2's seasonal cookery series What to Eat Now, decided to make a programme that explored the subject. And he's not alone: Jane Fearnley-Whittingstall (Hugh's mum) is bringing out a cookbook on the same theme.

But while Fearnley-Whittingstall Snr wants to see whether the experience of rationing has any lessons for our own economically straitened times, Warner had a different motive for making his Ration Book Britain. "I wanted to meet Marguerite Patten", he says. "Also, my grandmother had lived like she was on rationing until she died. She used to bite chocolates in half and wrap half the chocolate in cling-film and put it in the fridge – or even put half a boiled egg in the fridge. And my Mum had told me stories, and it was my – I don't know – duty to learn more, really."

Marguerite Patten, now aged 94, and Warner's mother, Simone, were both guests at the authentic austerity dinner party that Warner throws at the end of the programme. Margerite Patten began her long career, of course, devising recipes at the wartime Ministry of Food, eventually becoming the very first TV celebrity chef.

But more of that later, because in the meantime I had travelled to Warner's flat in Notting Hill to try and make some of the recipes featured in the programme. A former art student brought up in a food-obsessed household in Dorset ("Mum's jugged hare was exceptional, while we got very excited by dad's Laotian prawn curry ... He was British ambassador in Laos"), Warner has wanted to earn his living from cookery ever since realising he wasn't going to make it from the paintings that now decorate his flat. Having had his eyes opened to "keeping it simple" during a brief stint in the kitchens of the godfather of modern British cooking, Alistair Little, Warner was discovered by Pat Llewellyn, the legendary producer whose TV company, Optomen, gave us Two Fat Ladies and made stars of Jamie Oliver and Gordon Ramsay.

Now, it's not every day that a TV chef chops your vegetables for you round at his flat, but then there are precious few non-veggie ingredients in Woolton Pie – a wartime dish consisting mostly of potatoes and carrots that was invented by François Latry, maitre-chef of London's Savoy Hotel, and named after the Minister of Food, Lord Woolton. An editorial in The Times wasn't flattering: "When Woolton pie was being forced on somewhat reluctant tables, Lord Woolton performed a valuable service by submitting to the flashlight camera at public luncheons while eating, with every sign of enjoyment, the dish named after him."

Warner used the pie recipe printed in the Ministry of Food cookery book. "The dishes themselves weren't that bad, but what became apparent was the drudgery and boredom of eating this food, because in effect people had to eat it for 14 years." Indeed, Woolton Pie wasn't offensive as a one-off exercise – enlivened no end by herbs and a generous sprinkling of salt ("a lot of salt was used", says Warner. "It wasn't rationed") – but if this was all you had to look forward to between now and 2024, you might want to consider whether life was worth living.

People back then did anything to cheer themselves up, and this was the great age of ersatz dishes like "mock goose" – a combination of red lentils and breadcrumbs (see recipe, below right). The idea behind these mock dishes, Warner explains, "was that 'Wasn't it better to have goose in some form or other than to not have goose at all?' And then of course why would you want to call it 'lentils with brown bread stuffed in the middle'?

"It's like 'eggless sponge' and the idea that 'Isn't it better to sit down to some kind of tea cake than none at all?' Okay, it tasted slightly of baking powder and with a very miserable and mean scraping of jam in the middle, but at least you got a cake." Mock apricot was a little almond essence mixed with plum jam and grated carrots. Mock banana was parsnips mashed with a bit of banana essence.

But for me, what was actually more interesting than preparing these Ministry of Food recipes, was attempting to shop for authentic ingredients in a large west London branch of Tesco. The root vegetables were a doddle, of course, but when did you last try buying something advertising itself as "margarine"?

I was thrown by the cornucopia of butter substitutes – the seed oils, Utterly Butterly Omega 3s, soya dairy-free, cholesterol-lowerers, Benecol Buttery Tastes and the self-congratulatory I Can't Believe It's Not Butter – before being guided towards some Stork SB in the home- baking section. Mind you, even Stork these days prefers to describe itself as a "59 per cent vegetable fat spread". So plain old marge is out.

I noticed that corned beef and Spam still have a loyal following in Shepherds Bush. "I still like corned beef a lot", says Warner. "And I remember Spam from school and not liking it. But then when we were filming I saw the tin and said, 'Oh no, not the dreaded Spam'. But I was corrected and told that, no actually, it was a bit of a delicacy because it was from America."

One ingredient I could not find in Tesco for love nor money was that mainstay of rationing, powdered egg. "I ended up going to a specialist camping shop for mine", says Warner. "Powdered eggs are a bit nicer than they probably were, but we did the Ministry of Food fried egg, which was this wonderful invention."

Those with any outside space kept chickens, in which case they were given corn for the chicken instead of the powdered eggs. In fact the whole rationing system was surprisingly flexible, says Warner. "I was quite struck by the fact that the Ministry of Food took so much care in making sure that the diet was as balanced as it could possibly be, but also if you were a Muslim or Jewish or a vegetarian then you had options to swap rations over. So vegetarians would not take their bacon ration but take more cheese, Jews could actually get kosher meat, and so on."

What my rationing-minded visit to Tesco ultimately impressed on me was the extraordinary super-abundance which we now take so much for granted – and the waste that goes with it. "Nowadays as a nation we throw away a third of food without using it", says Warner. "There are lessons to be learned. When I was preparing carrots with Marguerite Patten she asked me why I was peeling them instead of washing them, and she cut the ends off much smaller – cut it off right at the top. It really was so waste-conscious – you had to be. You could be fined for wasting food." An unscripted example of the habits ingrained by 14 years of rationing and chronic food shortages arose spontaneously while filming the austerity dinner party sequence in Ration Book Britain. As is the way with these things, several retakes had to be filmed, by which time the veteran diners – Marguerite Patten, Warner's mother, and a former RAF bomber pilot, had wiped their plates clean. "We'd put more on the table", says Warner, "and Marguerite – this tiny, little, hunched-over 94-year-old – very kindly ate absolutely everything. They all did. Amazing."

'Ration Book Britain' premieres on the TV channel Yesterday on 15 January; 'The Ministry of Food' by Jane Fearnley-Whittingstall is published by Hodder & Stoughton on 4 February.

Wartime favourites: Recipes on rations

Woolton Pie

1lb King Edward potatoes
2lb carrots
lb mushrooms
1 small leek
2oz margarine or chicken fat
2 spring onions
Salt, pepper, nutmeg, chopped parsley
Bunch of herbs made of 1 small bay leaf, 1 small spring of thyme, parsley and celery.

Peel the potatoes and carrots, and cut them into slices the thickness of an old penny. Wash them well and dry in a tea-cloth. Fry them separately in a frying pan with a little chicken fat.

Do the same for the mushrooms, adding the finely chopped onions and leeks. Mix them together and season with salt, pepper and a little nutmeg and roughly chopped parsley.

Fill a pie dish with this mixture, placing the bundle of herbs in the middle. Moisten with a little giblet stock or water. Allow to cool. Cover with a pastry crust made from half beef suet or chicken fat and half margarine. Bake in a moderate oven for 1 hours.

Mock Goose

150g (6oz) split red lentils
275ml ( pint) water
15ml (1 tablespoon) lemon juice
Salt and pepper

For the stuffing:

1 large onion, chopped
50g (2oz) wholemeal fresh breadcrumbs
15ml (1 tablespoon) fresh sage, chopped

Cook the lentils in the water until all the water has been absorbed. Add lemon juice and season. Then make the 'stuffing'. Sauté the onion in a little water or vegetable stock for 10 minutes. Drain, and then add to the breadcrumbs. Mix in the chopped sage and mix well. Put half the lentil mixture into an oven-proof dish, spread the stuffing on top, and then top off with the remaining lentils. Put in a moderate oven until the top is crisp and golden.